An MTJ is employed in a non-volatile magnetic storage device. As a multilayer film which constitutes the MTJ (hereinafter referred to as MTJ multilayer film) includes transition metals, it has poor reactivity with a usually employed process gas. For this reason, an MTJ multilayer film is processed with a hard mask, and under conditions that strong physical sputtering can be performed. When processing is performed under such conditions, a marked shoulder drop occurs in the hard mask, resulting in inclination of the side surfaces of the patterned MTJ multilayer film. Because such an inclined surface is formed, it becomes difficult to micronize an area occupied by an MTJ device. In addition, the inclined side surfaces are susceptible to damage caused by plasma.
When etching an MTJ multilayer film, a product generated during the etching is likely to adhere to the side surfaces of the MTJ multilayer film. The product adhered to the side surfaces may cause an increase in leakage current. In the case where an ashing treatment is introduced to remove the adhered product, a tunnel barrier layer of the MTJ multilayer film is oxidized, and the thickness thereof is increased. Therefore, it is difficult to introduce an ashing treatment.
By depositing an MTJ multilayer film in a recess formed in an interlayer insulating film, it is possible to refrain from the use of shaping by the physical sputtering.
Japanese Unexamined Patent Application Publication Nos. 2001-284679 and 2002-299724 are examples of related art.